Latching relay



United States Patent 3,244,836 LATCHING RELAY Thomas E. Myers, St. Charles, TEL, assignor to Ideal industries Ind, Sycamore, ill, a corporation of Dela- Ware Filed Aug. 21, 1964, Ser. No. 391,226 10 Claims. ((31. 200-109) This invention relates to a latching relay in which the relay contacts are held in a closed position by mechanical means.

A primary purpose of the invention is a latching relay of the type described in which a movable pawl 18 held in one of two positions by spaced shoulders, the pawl belng moved from one position to another by a reset element having cam surfaces which cooperate with cam surfaces on the pawl.

Another purpose is a simply constructed reliably operable latching relay of the type described.

Another purpose is a positively operating latching relay utilizing a minimum of parts in the mechanical latching arrangement.

Another purpose is a latching relay of the type described utilizing an axially movable plunger to close and open the relay contacts.

Another purpose is a latching relay having a pair of elements with cooperating cam surfaces for locking and unlocking the relay contacts.

Other purposes will appear in the ensuing specification, drawings and claims.

The invention is illustrated diagrammatically in the following drawings wherein:

FIGURE 1 is a front elevational view of the latching relay with parts removed to show a portion of the latch ing mechanism;

FIGURE 2 is a view partly in section along line 22 of FIGURE 1;

FIGURE 3 is a rear elevational view;

FIGURE 4 is a view similar to FIGURE 1, but on an enlarged scale to illustrate the movement of the latch; and

FIGURE 5 is a view similar to FIGURE 4 to illustrate another operation of the latching mechanism.

Use of the same numerals in the different views will be a reference to the same structures and elements.

A latch holder or body section shown generally as has a side body member 11 which has a bottom opening 12, a top opening 14 and a passageway or looking channel 16 extending to both openings. The body section 10 has a top member which in the form shown has a pair of spaced sidewalls 18 and 20, a floor 22 therebetween, and an integral boss 24 projecting from the floor.

An electromagnetic coil shown generally as 26 is positioned below the top member, and this coil includes the usual core 28 having a threaded opening 36 engaged by screw 32 which passes through bore 34 in the boss. This screw also locks reed contacts 36 and 38 between the raised portion 40 of the top member and insulating plates 42 and 44. The reed springs 36 and 38 are normally biased to an open position. A top plate 46 is shown with a counterbore 48 which allows plate 46 to abut insulating plate 44 on the side of boss 24. Plates 42, 44 have openings to fit around the boss, and top locking plate 46 has an opening through which screw 32 passes.

The core shown herein is formed from a strip extending from the top 50 of an angled plate 52. The strip is bent downwardly and formed into the rounded core shape. Plate 52 has a side 53 with a slot 54 to receive in rocking relationship tongue 55 of armature 56. A flat angled spring 58 may be used to urge the armature away from the end 60 of the core.

The armature or actuating member 56 is adapted to be 3,244,836 Patented Apr. 5, 1965 attracted to the end of the core when the coil is energized. Such an action will move a reset element shown generally as 62 into contact with a latch shown generally as 64, and latch 64 raises plunger 66 which then moves reed 38 against reed 36 to thereby close the contacts. The reed spring 38 normally urges plunger 66 downwardly.

The details of the latching mechanism will be better understood by reference to FIGURES 4 and 5. The reset element or index 62 has a head 63 with point 65, a high face 67 and a low face 68. The faces form different angles to an imaginary line running along the longitudinal axis of the reset element. In the active position, the head 62 rests on stops at shoulders 72, 72a, extending from side walls or guides 73, 73a which define the pas sageway or locking channel 16.

The latch or pawl has a head 74 with lateral arrns'76 and 78. The body of the pawl is shown joining the head at an angle, and the foot 86 of the pawl has cam surfaces 82 and 84. These cam surfaces extend upwardly from point 87 at the foot of the pawl and are adapted to ride against either sidewall 73 or 73a. Arms 76, 78 of the pawl are adapted to engage and be seated upon offset shoulders 88 and $6 provided in the sidewalls or guides 73, 73a of the locking channel or passageway. Shoulders 88 and 96 are shown undercut, and shoulder 88 more so. When arm 76 is seated on lower shoulder 88, as shown in FIGURE 4, the latch mechanism is in an inactive position and the contact reeds 36, 38 are in the open position. When arm 78 is seated on higher shoulder 90, as shown in FIGURE 5, the head 74 has moved plunger 66 upwards so that element 94 on top of plunger 66 closes contacts 36, 38. The movement of reset element 62 will cause the latch or pawl 64 to successively change its lateral posi tion on each contact with the reset element as indicated by phantom outline 96 in FIGURE 4 and phantom outline 93 in FIGURE 5.

The use, operation and function of the invention are as follows:

The latching relay shown herein uses a mechanical arrangement to hold the relay contacts in either an open or closed position. The relay shown may have a wide variety of uses, for example controlling electric lights, electric motors, or any other type of control function in which a pair of relay contacts is to be closed and held in the closed position after receipt of a first pulse, and then opened and held in an open position after receipt of a second pulse, with the sequence of operation repeating upon the receipt of successive pulses.

Assuming that the contacts are in the open position, and the pawl is in the position of FIGURE 4, when the electromagnet 26 receives a pulse of current armature 56 will move in an upward direction to move reset element 63 toward the pawl. Cam surface 67, which as shown herein is generally straight, will contact somewhat arcua te cam surface 84 on the pawl to swing the pawl in a clockwise direction as it moves the pawl upward. Arm 76 will be moved off should 88. The pawl will move upwardly and will push plunger 66 ahead of it to close the contacts. After the armature has moved away from the reset element, indicating a drop in current or the end of the current pulse supplied to the electromagnet, the pawl will be in the dotted line position of FIGURE 4 and the relay contacts will be held in a closed position.

Upon the receipt of the next pulse of current, the armature will again be moved upward and reset element will move up to contact the pawl. Cam surface 68 on the reset element, which is again generally straight, will contact the somewhat arcuate cam surface 82 on the pawl to swing the pawl laterally or in a counterclockwise direction. Once the reset element drops, the pawl will drop as its arm '78 will have moved off shoulder 90. The pawl will then be held by shoulder 88.

assesses The invention should not be limited to a relay arrangement in which the channel is offset to one side of the electromagnet. The elements described and shown can also be concentric with the axis of the electromagnet. Other satisfactory arrangements are also possible.

The material forming the contact elements should be sufiiciently flexible so that the contacts may be easily closed when the plunger 66 moves upwardly and so that the contacts will immediately spring apart once the plunger moves down.

Whereas the preferred form of the invention has been shown and described herein, it should be realized that there are many modifications, substitutions and iterations thereto within the scope of the following claims.

I claim:

1. In a latching relay, a housing, a pair of normally open contacts on said housing, an electromagnet in said housing, an armature mounted on said housing, spring means urging said armature away from said electromagnet, a channel in said housing adjacent said contacts, a pawl positioned for movement in said channel, means in said channel for holding said pawl in a first fixed position in which the pawl is effective to hold the contacts in a closed position, and to hold said pawl in a second fixed position in which the contacts remain in an open position, and a reset element in said channel positioned for contact by said armature and pawl, said reset element and pawl having cooperating cam surfaces whereby said reset element moves said pawl from one of said two fixed positions to the other for each operation of said armature.

2. The structure of claim 1 further characterized by a pair of spaced shoulders in said channel, said pawl having arms positioned for contact with said shoulders to hold said pawl in One or other of said two positions.

3. The structure of claim 1 further characterized and including a plunger in said channel positioned between said contacts and said pawl, movement of said pawl in said channel being effective to move said plunger toward and away from said contacts.

4. The structure of claim 1 further characterized in that said reset element is el fective to axially move the pawl in the channel, with the cooperating cam surfaces causing said pawl to swing laterally in the channel as it moves axially.

5. In a latching relay, a housing, a pair of normally open relay contacts on said housing, an electromagnet in said housing, an armature mounted on said housing, spring means urging said armature away from said electromagnet, a pawl positioned for movement toward and away from said contacts, means on the housing for holding said pawl in a first fixed position in which the pawl is eifective to hold the contacts in a closed position and to hold said pawl in a second fixed position in which the contacts remain in an open position, a reset element positioned to contact said pawl and positioned for contact by said armature, said reset element and pawl having coopcrating cam surfaces whereby said reset element moves said pawl from one of two said fixed positions to the other for each operation of the armature.

6. The structure of claim 5 further characterized in that said reset element is effective to axially move the pawl, with the cooperating cam surfaces causing said pawl to swing laterally as it moves axially.

7. The structure of claim 6 further characterized in that the cam surfaces on the pawl are slightly arcuate, with the cam surfaces on the reset element being generally straight.

8. The structure of claim 5 further characterized in that said reset element and pawl are in axial alignment.

9. The structure of claim 5 further characterized in that the means on the housing for positioning the pawl include a pair of shoulders spaced different distances from the contacts.

Iii. The structure of claim 9 further characterized in that said pawl includes a pair of laterally extending arms adapted to seat on said shoulders.

No references cited.

BERNARD A. GILI-IEANY, Primary Examiner. 

5. IN A LATCHING RELAY, A HOUSING, A PAIR OF NORMALLY OPEN RELAY CONTACTS ON SAID HOUSING, AN ELECTROMAGNET IN SAID HOUSING, AN ARMATURE MOUNTED ON SAID HOUSING, SPRING MEANS URGING SAID ARMATURE AWAY FROM SAID ELECTROMAGNET, A PAWL POSITIONED FOR MOVEMENT TOWARD AND AWAY FROM SAID CONTACTS MEANS ON THE HOUSING FOR HOLDING SAID PAWL IN A FIRST FIXED POSITION IN WHICH THE PAWL IS EFFECTIVE TO HOLD THE CONTACTS IN A CLOSED POSITION AND TO HOLD SAID PAWL IN A SECOND FIXED POSITION IN WHICH THE CONTACTS REMAIN IN AN OPEN POSITION, A RESET ELEMENT POSITIONED TO CONTACT SAID PAWL AND POSITIONED FOR CONTACT BY SAID ARMATURE, SAID RESET ELEMENT AND PAWL HAVING COOPERATING CAM SURFACES WHEREBY SAID RESET ELEMENT MOVES SAID PAWL FROM ONE OF TWO SAID FIXED POSITIONS TO THE OTHER FOR EACH OPERATION OF THE ARMATURE. 